Production of Bifunctional Molecules By Clostridium Sp. BOH3

Title

Production of bifunctional molecules by Clostridium sp. BOH3

Abstract

Clostridium sp. BO3 produces high yield of butanol and volatile fatty acids (predominantly acetic and butyric acids) from simple sugars and polysaccharides. When sp. BOH3 is cultured in reinforced clostridial medium with glycerol and sugar alcohols including mannitol, galactitol, sorbitol and xylitol, it produces bifunctional molecules including succinic acid and 1,3 propanediol (PDO). These bifunctional molecules are important feedstocks for various applications. For instance, succinic acid is as a precursor for the production adipic acid, 1,4 butanediol, terahydrofuran and g-butyrolactone. Similarly, PDO is used for the production of polymers, cosmetics and lubricants. The strain BOH3 produces 6.8±0.2 g/l of PDO and 1.3 g/l of succinic acid as major fermentation products from 30 g/l of glycerol. Meanwhile, it produces high level of succinic acid (>5g/l) and low concentration of (< 2 g/l) of PDO from sugar alcohols. Among the selected sugar alcohols, mannitol (30 g/l) supports 7.2±0.2 g/l of succinic acid and 1.3±0.2 g/l of PDO after 5 days of fermentation. In batch fermentation, a higher initial concentration (> 30 g/l) of glycerol and mannitol did not inhibit the growth of sp. BOH3, and did not support the production of succinic acid and PDO. While employing fed-batch process, addition of 30 g/l of glycerol and mannitol after 3 days of fermentation is able to enhance the production of PDO and succinic acid to 12.6±0.2 and 10.6±0.3 g/l respectively. Furthermore, addition of Na₂S at lower concentration (0.2 g/l) supports the PDO production (15.6±0.2 g/l) from glycerol. Meanwhile, CaCO₃, and NaHCO₃ (2.5-5 g/l) enhance the production of succinic acid to 16.9±0.5 g/l from mannitol. Overall, the fed-batch production process result the yield of PDO and succinic acid as 0.26±0.005 g /g of glycerol and 0.28±0.008 g / g of mannitol, respectively. To best of our knowledge, this is first report deals the production of succinic acid by solventogenic Clostridium strain.